Wanted: Custom Audio Solution

by Mez on Jul.25, 2008, under Personal

This is a sort of “Dear LazyWeb” post.

As I’m moving to a new place on sunday, I’m going to have some restrictions on when I can use loudspeakers (so as to not disturb other people), but at the moment, I’ve got a few places where I’m using different audio sources, for example, when I’m using my PC, I might be either playing music through my PC, listening to the DAB Radio I have in the background, watching TV at the same time, etc etc.

What I need (want) is a solution so that I can have a box on my desk which allows me to select from a range of inputs, and flick between outputting to the speakers, or to headphones.

While at the moment, every item I have seperate speakers. My Surround has 4 inputs (1 aux, 3 for surround – all 3.5mm Jacks) and my headphones have a single 3.5 mm jack.

What I’d like to do is be able to wire the following into a box, and then have a button to switch between using the speakers on the surround, and the headphones.

PC – 3 3.5mm Jacks for surround
Laptop – Single 3.5mm Jack
DAB Radio – single 3.5mm Jack
TV – single 3.5mm Jack
Mixer – currently going through PC, but has 2 x Mono 1/4″ jacks out (which I’ve already converted to a single 3.5mm Jack at the other end)

I’d like it if I could listen to multiple resources at the same time. However, at the moment, I think that the main issue is going to be converting the Surround into stereo for the headphones… The single 3.5 Jacks can be output to the “Aux” channel…

I don’t know if anyone knows of any solutions for this, or wants to help me build one (anyone good with creating circuit diagrams) – and I’m sure there’ll be issues with different sources.

I mean, I could probably just pipe all but the surround through the mixer… and then use the headphone override on the speakers, but I don’t really want to have the issue of plugging and unplugging the headphone jack all the time. I’d rather just hit a button.

Any thoughts?

:audio

10 Comments for this entry

tamoneya
July 25th, 2008 on 6:28 pm
if you are comfortable enough with electrical components you could just make a variable summing opamp.
http://www.ecircuitcenter.com/Circuits/opsum/opsum.htm

V1, V2, V3 would be your three inputs. You should put potentiometers (variable resistors) in for R1, R2, R3. This will allow you to mix the sounds. Then Vo goes to your speakers.
Mez
July 25th, 2008 on 6:41 pm
Unfortunately, while that’ll combine the inputs, it doesn’t fix the
other issues, like being able to switch between different outputs,
convert 5.1 to stereo, or route the sound differently dependant on a
switch state.

Though it does fix one major issue. I’m sure if I knew more about
electronics, I could come up with a really nice Circuit Diagram from
this to do what I need it to do…. though working with 2 channels,
keeping the potentiometers in sync with each other, etc etc…

It’s a start though
TheGZeus
July 25th, 2008 on 7:38 pm
Sounds like you want a Reciever.
Any modern Home Theater reciever (even bottom barrel ones) should do the trick. Find a Pioneer from a few years back, even.
djurodrljaca
July 25th, 2008 on 7:50 pm
It would help if you could write what are your “capabilities” with electronics.

If you get a circuit diagram, can you build the circuit?

The circuit shouldn’t be a problem.
- The surround: you can use a summing op. amp. so you get “stereo” from surround (no need for potentiometers here)
- Mixer: another summing op. amp. with potentiometers so you can regulate the volume of every source
- output selection: you can use a simple switch to switch between the speakers and headphones

You can get “stereo” potentiometers for volume control and “stereo” switch for output selection. You can also use “stereo” switches to enable/disable sources.
blueget
July 25th, 2008 on 9:19 pm
We’ve got something like that at School, you can switch there between the PC, the DVD Player and the Video Recorder. Unfortunately I can’t really find out what vendor it is from and where to get it since we have big school holidays until september here in Austria. The surround sound is likely to be problematic, because the box I know only can handle stereo sound from single 3,5 mm Jacks, but maybe there are other models that can cope with surround sound. Oh, and it also doesn’t have any mixer, you can just switch between the different sound sources.

I’ll post again here as soon as I found out where to get these boxes.
Justace Clutter
July 25th, 2008 on 9:57 pm
Or you could just…. get a mixer…..
Mez
July 25th, 2008 on 10:29 pm
It seems that I haven’t made it clear.

What I need to be able to do is mix down several inputs (one of them is 3 inputs for Surround Sound). I then need to be able to switch those inputs from my Surround System to my headphones.

I already have a mixer, however, this only deals with Stereo, not with surround sound… While I could mix everything from the surround down to stereo, pass through the mixer, then back out to “fake” surround from the mixer, I don’t want to do this, I want proper surround sound being sent to the surround sound, with the stereo mixed in. It’s not really an easy thing to do, and would probably need something custom made.

Plus, you have the fact that generally, your difference between control room and master out for mixers would mean that you’d have to press several buttons to actually switch everything. While this is nice as you can select some items for speakers, and some for headphones… It’s not exactly what I want to do.
shew
July 26th, 2008 on 4:38 pm
TheGZeus hit the nail on the head. A receiver is what you need.
fb
July 27th, 2008 on 2:58 am
Crazy suggestion but how about using your mixer to mix the stereo sources and pass the result into the AUX input on your sound card and use the sound card for output.

This way you’ll have all stereo sources premixed via the mixer and still be able to retain the surround from the sound card.

Alternatively, you could use the multiple CD/AUX inputs into your sound card directly and use the sound card’s mixer to mix the sources. I’m not sure how many sources exactly that you’d like to input but most sound cards these days can handle at least 2 to 3 input sources between the external jacks and the internal plugs (you may need to create a custom adapter to convert the 3.5mm jack to a 4-pin CD-style connector).
jim dorey
August 8th, 2008 on 4:09 pm
i’ve got a circuit i made up a while ago, it’s 8 channel s-video, composite and stereo, could be modified. i actually have several, it was for fun.